1. Field of the Invention
The present invention relates in general to a digital/analog recording/playback system which is capable of recording and playing back a digital video signal as well as an analog video signal and which is compatible with an existing VHS system, and more particularly to a tracking control apparatus and method for a digital/analog recording/playback system in which, during recording of a digital video signal by heads for recording such a digital video signal, a tracking signal is separately recorded by heads for the analog video signal so that a loss of the digital video signal can be reduced.
2. Description of the Prior Art
Generally, a video signal is recorded on tracks of a tape by heads and the recorded video signal is played back as the tracks are traced by the heads. Also, a tracking signal is recorded on the tape in a wound direction thereof as a control signal for the track tracing. The recording of the tracking signal is performed in the unit of a frame of the video signal or an integer multiple of frames thereof. The playback of the recorded video signal is performed by the heads with the recorded tracking signal played back.
In a conventional method of recording and playing back a tracking signal, the tracking signal is recorded on a particular track of the tape at an interval of a frame of the video signal or an integer multiple of frames thereof. For this reason, a tracking error cannot be obtained with respect to all tracks of the tape.
In another conventional method of recording and playing back a tracking signal, the video signal and a pilot signal as the tracking signal are recorded on the same track of the tape. The tracking error is obtained by comparing pilot signal levels of the adjacent tracks with each other in the playback. In this method, the tracking error can be obtained with respect to all tracks of the tape. This makes it possible to control a tracking error component which may be generated when the heads trace the corresponding tracks of the tape leaning to the left and right thereof. However, the latter method has a disadvantage in that a recording frequency band of the video signal is reduced by that of the pilot signal because it is recorded on the same track together with the pilot signal, overlapping with the pilot signal. This results in a degradation in a signal-to-noise ratio of the video signal. On the other hand, a digital video signal must be recorded with density much higher than that of an analog video signal for a predetermined time period since it has a recording amount (about 5 times) much more than that of the analog video signal. In this connection, the latter method has another disadvantage in that the digital video signal experiences a large loss because it is recorded on the same track together with the tracking signal.